The situation demands action, and action is on its way. As the gap between petroleum-based fuel production and demand continues to widen, the aviation industry has become active in its search for a viable fuel alternative. While great progress in alternative fuel development has been made during the past few years, U.S. industry has yet to see anything new on the market. Some innovative companies, however, are looking to change that as soon as possible. Who will bring their new and improved fuel into commercial use first, possibly ending petroleum-based fuel consumption in the skies forever?
The ideas for alternative aviation fuel are abundant, but only a handful are feasible for immediate production and consumption. Alternative fuels can be placed into three categories: synthetic fuels; bio-fuels; and hybrid, electric, or hydrogen fuel technology.
In order to utilize hydrogen fuel technology in aircraft, major engine and airframe modifications must be made, including the adoption of a large, heavily insulated hydrogen fuel tank. On top of that, the entire fuel supply infrastructure would have to be switched out.
Hydrogen technology could be the best solution for long-term sustainability, but it does have drawbacks. While burning hydrogen is clean, hydrogen is currently produced from natural gas or other hydrocarbons. CO2 is released as a byproduct of this conversion process. However, the hydrogen production CO2 quantity is less than the CO2 produced from a gasoline powered car by approximately 50% - a significant improvement. New hydrogen production technologies under study offer hope of a cleaner, more efficient production.
The more viable options lie in the realm of synthetic and/or bio-fuel blends which can directly replace (drop-in) petroleum-based fuels without any modification to either aircraft or fuel supply infrastructure.
Approval for these fuels, however, is another story.
VYING FOR APPROVAL
Alternative fuel candidates must pass stringent specification requirements in order to assure the safe and reliable operation of aircraft. The “high hurdles” that aviation fuel must overcome are considerably more rigorous than fuel for ground transportation because of the different set of safety criteria for aircraft.
Nancy Young, Vice President of Environmental Affairs at the Air Transport Association (ATA), says that working with companies and airlines which are developing alternative fuels is critical so that everyone involved is speaking the same language regarding the end product.
“It’s even more critical to the airlines that we be involved and encourage suppliers that if they make it through the [certification] process, that we will be there to buy their product,” says Young.
“That’s part of what ATA is doing as a founding and principle member of the Commercial Aviation Alternative Fuels Initiative (CAAFI).”
CAAFI was established to aid in the exploration, development, and certification of alternative fuels. The organization includes a range of participants from the international commercial aviation community.
“CAAFI works with FAA in order to help in the certification, qualification, and the research and development of alternative aviation fuels,” says Hank Price of the office of communication for environment and energy at FAA.
“Our major goal is a fuel than can offer equivalent levels of safety and is comparably favorable to petroleum-based jet fuel, both on cost and environmental effects.”
Price admits that the industry must first approve an alternative “drop-in” fuel which will be gradually replaced by more efficient and environmentally friendly fuels as they are developed.
Some specific requirements for alternative aviation fuel include: smooth boiling range distribution; high energy output; thermal conductibility; storage stability; and freezing point, just to name a few.
ASTM International, an organization which develops technical standards for design, manufacturing, and trade in the global market, has approved only two types of jet fuel for commercial use: the standard petroleum-based fossil fuel we use today, and a synthetic fuel produced by the South African company, Sasol.
According to ATA’s Young, ASTM is looking to approve, by the end of this year, a revision to the jet fuel specification which will allow up to a 50 percent blend of synthetic fuel and existing fossil fuel.
Young says ATA is trying to take the same approach for a revision which will approve up to a 50 percent bio-fuel blend by 2010.
George Bye, CEO of Bye Energy Inc. based in Colorado, has committed his company to addressing what he describes as “a very urgent need for renewable fuels which are able to be produced domestically.”
Bye Energy has been busy researching various plant-based feed stocks for use in alternative fuel production.
When looking at feed stocks, Bye says it’s important that the candidate feedstock does not have any direct human impact, such as the depletion of a human food source like corn or soy.
Bye considers algae a promising feedstock because it contains a high energy density and grows prolifically (nearly doubles in mass every 24 hours). While Bye admits that algae are a great candidate as a potential feed stock, he stresses the fact that his company is indifferent to any particular technology.
“We want to be a conduit of these various technologies to provide clean renewable solutions for aviation fuel,” says Bye. “We do not prefer one over another at this point, but we want to evaluate the technologies that are out there. We don’t want this to be a ten-, or 20- year solution; we want to get into a phase of analysis large enough that we can evaluate the technology for commercialization in the near term.”
Bye Energy has a two-phase process for helping companies bring a viable alternative aviation fuel to market. The first phase is an analysis of the various alternative fuel technologies including three test sites. In this phase, Bye invites various companies and research universities into an agreement with his company at a scale large enough so that his company can analyze the capabilities of each technology for commercialization.
The second phase involves choosing candidates based on the test analysis of phase one; candidates chosen will then work for Bye under contract to provide fuel to the aviation industry.
“We think the technology has matured enough from several locations…, the field of players is big enough that we will likely find those technologies that are ready for commercialization within the next two to three years,” says Bye.
As far as price goes, Bye says the fuel must be competitive with fossil fuel. Companies come to Bye Energy certain their technologies can produce an alternative aviation fuel at a competitive price; that’s when Bye says to them: “Ok, now show me.”
“The real challenge is scaling the technology up and demonstrating out of the lab, getting out of the research circle, and getting into the field,” says Bye. “That’s where we get into the real challenges of the technology- engineering, logistics, and infrastructure that you have to face when making fuel for airplanes.”
The Boeing Company, also a contributing player in CAAFI, is currently promoting the development of sustainable biofuels for commercial aviation use. Boeing’s managing director of environmental strategy, Billy Glover, gave a presentation on sustainable biofuels at ACI’s annual event in Boston last month.
The basis of Boeing’s biofuel initiative is fundamental: creating viable fuels from renewable resources. Some resources the company has been researching include feedstock such as algae, jatropha, halophytes, and non-food cellulose. The candidates must prove that a viable supply model can be created and that they can be blended with the petroleum-based fuel used today as a “drop in” application.
Alternatives to petroleum-based fuel have already been tested in Boeing commercial jets by way of flight demonstrations. A flight test took place earlier this year with Virgin Atlantic and GE, the first ever commercial flight using the bio-fuel blend. Glover also noted that an Air New Zealand and Rolls Royce test flight will take place later this year followed by Continental Airlines and CFM.
“It turns out, we are able to produce fuel that actually performs as good as or better than the petroleum-based fuel we use today,” says Glover.